28123 Parallax Inc, 28123 Datasheet - Page 171

• Manufacturer Part Number: 28123
• Description: TEXT WHAT'S A MICROCONTROLLER
• Manufacturer: Parallax Inc
• Type: Programmingr

Specifications of 28123

• Style: Book
• Title: What's a Microcontroller?
• Contents: Whats a Microcontroller? Text
• Product: Microcontroller Accessories
• Core Processor: PIC16C57c
• Flash: 128 Bytes
• Operating Supply Voltage: 9 V
• Board Size: 31 mm x 16 mm
• Lead Free Status / RoHS Status: Not applicable / Not applicable

P2. The key is to add
LOOP
' What's a Microcontroller - Ch5Prj02_ControlServoWithPot.bs2
' Read potentiometer in RC-time circuit using RCTIME command.
' The time variable ranges from 126 to 713, and an offset of 330 is
' needed.
' Modify so the servo only rotates from 650 to 850.
' {$STAMP BS2}
' {$PBASIC 2.5}
DEBUG "Program Running!"
time VAR Word
DO
LOOP
prevTime = time
HIGH 7
PAUSE 10
RCTIME 7, 1, time
time = time + 330
IF ( time > prevTime + 2) THEN
ELSEIF ( time < prevTime - 2) THEN
ELSE
ENDIF
PULSOUT 14, time
HIGH 7
PAUSE 10
RCTIME 7, 1, time
time = time + 330
IF (time < 650) THEN
ENDIF
IF (time > 850) THEN
ENDIF
PULSOUT 14, time
HIGH 13
LOW 12
LOW 13
HIGH 12
LOW 13
LOW 12
time = 650
time = 850
IF…THEN
blocks; an example is shown below.
' Read pot with RCTIME
' Scale time to servo range
' Constrain range from 650 to 850
' Store previous time reading
' Read pot using RCTIME
' Scale pot, match servo range
' increased, pot turned CCW
' Bi-color LED red
' value decreased, pot turned CW
' Bi-color LED green
' Servo holding position
' LED off